Present techniques of determining key parameters of amplitude modulated and single sideband receivers under test, i.e., receiver sensitivity bandpass characteristics and receiving frequency utilize a large signal generator used in conjunction with an oscilloscope and power meter. While such equipment is suitable for manual operation it is not adaptable to automated testing techniques. Signal generators which are adaptable to automated testing techniques, i.e., can be computer controlled are both complex and expensive. In many cases these equipments have capabilities which are far beyond automated testing requirements, resulting consequently, in the associated high cost of over design. Specifically these equipments typically will tune to within ten cycles of any desired frequency while in many cases it is sufficient to have limited frequency generating capabilities coupled with adaptability to computer control.